Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32
From: Nicolas Saenz Julienne
Date: Wed Sep 11 2019 - 06:54:44 EST
On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote:
> - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). It
> - * currently assumes that for memory starting above 4G, 32-bit devices will
> - * use a DMA offset.
> + * Return the maximum physical address for a zone with a given address size
> + * limit. It currently assumes that for memory starting above 4G, 32-bit
> + * devices will use a DMA offset.
> -static phys_addr_t __init max_zone_dma32_phys(void)
> +static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
> phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, 32);
> - return min(offset + (1ULL << 32), memblock_end_of_DRAM());
> + return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM());
while testing other code on top of this series on odd arm64 machines I found an
issue: when memblock_start_of_DRAM() != 0, max_zone_phys() isn't taking into
account the offset to the beginning of memory. This doesn't matter with
zone_bits == 32 but it does when zone_bits == 30.
I'll send a follow-up series.
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